The Kyushu Office has relocated and is now fully operational. The company is piloting a new compact office design aimed at fostering interaction between employees and external stakeholders.
In an existing tenant building over 20 years old, the project aims to reduce operational energy consumption by 40 percent. This marks the second phase of a renovation demonstration project based on collaboration between the building owner and tenants.

Nikken Sekkei Ltd. (Headquarters: Chiyoda-ku, Tokyo; Representative Director President and CEO: Atsushi Omatsu; hereinafter “Nikken Sekkei”) relocated and renovated its Kyushu Office (hereinafter “the Office”) to the 5th floor of the same building and began full-scale operations on the new floor in February 2026.

Nikken Sekkei is conducting pilot projects at its offices across the country to gain firsthand experience with social issues and implement solutions in society. This initiative marks the fourth in a series, following projects in Tokyo, Osaka, and Hokkaido.At this office, located in an existing tenant building over 20 years old, the building owner and tenant (Nikken Sekkei) are working closely together to promote environmental retrofits, aiming to achieve a ZEB-oriented retrofit* that reduces energy consumption by 40% during the operational phase.

Currently, the real estate industry is required to reduce CO2 emissions by 51% by 2030 compared to fiscal year 2013 levels. However, just under 70% of the nation’s office building stock is more than 20 years old, making it an urgent priority to improve the environmental performance of these existing buildings.Generally speaking, compared to company-owned buildings, “tenant buildings”—where the owner and the tenant are different entities—face the challenge of difficulty in reaching consensus on environmental retrofits, making it hard to advance decarbonization efforts. In light of this situation, the Ministry of the Environment has introduced the “Leading Tenant Action Guidelines,” and initiatives from tenant companies are now expected.Furthermore, in recent years, corporate management has placed greater emphasis on addressing Scope 3 emissions (emissions across the entire supply chain), and occupying environmentally friendly buildings has become a key factor influencing corporate value.

In 2023, Nikken Sekkei demonstrated a 47% reduction in energy consumption in an existing tenant building—the Osaka Office (Ginsen Bingo-cho Building)—through environmental retrofits carried out in collaboration with the building owner.This office (Kamiyo Watanabe Building) marks the second phase of this “environmental retrofit through owner-tenant collaboration.” While the Osaka office was a large-scale building with a total floor area exceeding 30,000 square meters, this project demonstrates that similar initiatives are feasible even in a medium-sized building such as this one, with a total floor area of approximately 8,600 square meters.In collaboration with the building owner, Kamiyo Holdings Co., Ltd. (operated by Kamiyo Sangyo Co., Ltd.), we aim to reduce energy consumption by 40% (targeted value) compared to the office building standard* by implementing the following renovations.
*Calculated using the WEB Program Standard Input Method

This initiative combines “owner-led initiatives” aimed at improving the building’s fundamental performance with “tenant-led initiatives” designed to foster a shift in employees’ mindsets.
Owner-led Initiatives (Physical Renovations):
Measures include enhancing the thermal insulation of window glass in private units, adding a “natural ventilation mode” to allow outside air to enter seasonally, and installing motion-sensor-activated lighting in common areas. With a view to improving the energy efficiency of the entire building, Nikken Sekkei has already completed environmental retrofits on the 5th floor, where its offices are located, as a pilot project.

Initiatives by the tenant (Nikken Sekkei) (operational aspects):
Based on the “My OFFICE” concept, the building incorporates a style where employees adjust their own work environment.
Lighting: By reducing the illuminance in the workspace (300 lux on desks) and combining general lighting with spotlights, we have achieved precise control over the lighting environment. We have created a workplace where employees can concentrate comfortably on their work without wasting electricity.
Ventilation: Circulators are installed above the windows. By combining this with natural ventilation and allowing workers to control the air conditioning via IoT devices, the design enables active environmental adjustment.

Establishment of the Co-creation Space “PYNT Kyushu”
Nikken Sekkei has established “PYNT Kyushu” as the Kyushu branch of “PYNT,” a network of co-creation hubs for solving social issues that the firm operates nationwide. It will serve as a co-creation hub in Kyushu where diverse stakeholders from both inside and outside the company can connect and collaboratively nurture new ideas.

Office Design That Fosters Interaction by Making the Most of a Compact Workspace
Based on the “nest” concept—which signifies a comfortable space where workers can create their own personal spaces—the office adopts an experimental layout within the limited space. Rather than the typical arrangement of desks facing each other (opposite-island style), desks are connected in a zigzag (staggered) configuration.This not only makes it easier for the eyes of people walking down the aisle to naturally meet those of people seated at their desks, but also—with the corners of the desks facing the aisle—makes it easier for nearby colleagues to stop by, creating an environment that encourages conversation.Furthermore, by creating an “unobstructed diagonal line of sight” that extends all the way to the edge of the office, we are experimenting with a workplace design that, while compact, does not feel cramped—one that fosters a sense of unity across departments and encourages spontaneous communication.

Local Production for Local Consumption Using Materials from Kyushu
We actively utilize materials produced throughout Kyushu and natural materials in the finishes of door and window fixtures and furniture, thereby balancing contributions to the local economy with the reduction of environmental impact.

Over the next year, we will collect actual operational data to verify the energy-saving effects. We aim to apply these findings not only to our own floor (the 5th floor) but also to other floors throughout the building and to similar existing tenant buildings across Japan.Building on our track record in Osaka and Kyushu, we will continue to collaborate with a diverse range of building owners to promote ZEB-oriented retrofits of existing buildings, thereby contributing to the decarbonization of the entire construction industry.

*ZEB-oriented retrofit: A retrofit that aims to maximize energy savings within the constraints of an existing building, in accordance with the definition of ZEB (Net Zero Energy Building).

[Entire Building] Address: Kamiyo Watanabe Building, 1-12-14 Tenjin, Chuo-ku, Fukuoka City, 810-0001 / Site Area: 1,012.90 m² / Building Footprint: 833.13 m² / Total Floor Area: 8,628.76 m² / Number of Floors: 10 above ground, 1 below ground, 1 penthouse floor / Building Height: 40.65 m / Structure: SRC (partially RC and S) / Completion: October 2000
[Kyushu Office (5th Floor)] Exclusive Use Area: 602.44 m² (182.23 tsubo) / Floor-to-Floor Height: 4.0 m / Ceiling Height: 2.7 m / Raised Floor Height: 100 mm

Nikken Sekkei is a professional services firm specializing in architectural and civil engineering design and supervision, urban design, and related research, planning, and consulting services. For 125 years since its founding in 1900, Nikken Sekkei has been committed to creating value through "social environment design," which aims to solve both explicit and implicit social issues, in order to meet the demands of society and the diverse needs of its clients. To date, it has been involved in various projects in Japan, China, ASEAN, and the Middle East, and in recent years has expanded into India and Europe.

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